Many routine treatments employed in modern clinical practice involve percutaneous insertion of needles and catheters for biopsy and drug delivery and other therapies. The aim of a needle insertion procedure is to place the tip of an appropriate needle safely and accurately in a target region, which could be a lesion, organ or vessel. Examples of treatments requiring needle insertions include vaccinations, blood/fluid sampling, regional anesthesia, tissue biopsy, catheter insertion, cryogenic ablation, electrolytic ablation, brachytherapy, neurosurgery, deep brain stimulation and various minimally invasive surgeries.
Guidance and steering of needles in soft tissue is a complicated task that requires good 3-D coordination, knowledge of the patient anatomy and a high level of experience. Therefore robotic systems have been proposed for performing these functions. Among such robotic systems are those described in U.S. Pat. No. 7,008,373 to D. Stoianovici, for “System and method for robot targeting under fluoroscopy”; and in U.S. Pat. No. 5,572,999 to Funda et al, for “Robotic system for positioning a surgical instrument relative to a patient's body”; and in the product data sheets on the Innomotion robot, as provided by Innomedic GmbH, of Philippsburg-Rheinsheim, Germany.
All of these systems are guiding systems that help in choosing the insertion point and in aligning the needle with the target. The insertion is then done by the surgeon who pushes the needle along the straight line. Such systems usually work with 3-D data taken before the procedure, typically by CT or MRI. The 3-D reconstruction of the patient anatomy is done first. Then the needle is registered to the 3-D anatomy and the robot can orient a cannula so that it will be aligned with the target. Through that cannula the doctor inserts a needle assuming that the needle will not deviate from a straight line and that it will hit the target. A problem with this method is that both needles and tissue are flexible and the needle therefore does not always proceed in a straight line even in soft tissue. It may deviate from the planned straight path, and methods are needed for ensuring that it does reach the intended target region.
A method for needle steering which is based on the lateral forces exerted on the tip of flexible beveled needle has been described in published US Patent Application US 2007/0016067 A1 to R. J. Webster III et al, for “Distal Bevel Tip Needle Control Device and Algorithm”. This application describes a needle driver which grasps the base of the beveled needle and drives the needle shaft by pushing it for longitudinal entry, and rotating it for steering.
In PCT publication No. WO 2007/141784 to D. Glozman et al, for “Controlled Steering of a Flexible Needle”, there is described another method in which the base of the needle is held by a robot, and the needle is steered by manipulation of the needle base by the robot.
However, all of the methods and systems described above use needles gripped robotically or otherwise, at their proximal ends, remote from the insertion point into the patient. This results in the need for a large workspace, which may be especially problematic in the realm of imaging systems, where headroom above the supine patient is often limited. There therefore exists a need for a more compact method of manipulating a needle during the insertion process into a subject.
The disclosures of each of the publications mentioned in this section and in other sections of the specification, are hereby incorporated by reference, each in its entirety.